Monolithic Plates Research Articles

On the contact behavior of aluminum plate targets subjected to ogive nosed projectile impact

This study presents the effect of contact friction on the impact resistance of monolithic aluminum 1100-H12 plate targets against ogive nosed EN24 steel projectiles. The projectiles were propelled using a pneumatic air pressure gun against circumferentially clamped circular targets measuring 255 mm in diameter. The initial as well as residual velocities of the projectile were captured using a high-speed camera working at 10,000 fps. Finite element modelling of the ballistic impact was carried out using ABAQUS/Explicit module. Johnson-Cook strength and damage model was employed to model the flow and fracture characteristics of the target material, whereas, the projectile was modelled as a rigid body. The coefficient of tangential friction between the surfaces of projectile and target was varied and its influence on the deformation and the failure of the targets was investigated. The ballistic performance of the aluminum targets was compared in terms of velocity drop, ballistic limit, local as well as global target deformations and energy absorption in the target.

Elastic plate under low velocity impact: Classical continuum mechanics vs peridynamics analysis

<abstract><p>The aim of this paper is to compare the classical continuum mechanics and the peridynamic models in the structural analysis of a monolithic glass plate subjected to ball drop. Governing equations are recalled in order to highlight the differences and basic features of both approaches. In this study the behavior of glass is assumed to be linear-elastic and damage processes are ignored. The generalized Hooke's law is assumed within the classical theory, while the linear peridynamic solid constitutive model is applied within the peridynamic analysis. Mechanical models for the ball drop simulation are discussed in detail. An emphasis is placed on the discretization including finite element mesh, peridynamic node lattice and time stepping, as well as appropriate constraints and contact conditions in both finite element and non-local peridynamics models. Deflections of the plate after the ball drop are presented as functions of time and the results based on the finite element and peridynamic analysis are compared. Good agreements between the deflection values in selected points of the plate as well as deflection fields at several time points indicate, that the model assumptions for the non-local peridynamic analysis including the horizon size, the short-range force contact settings and the support conditions are well suited. The developed peridynamics models can be applied in the future to analyze damage patterns in glass plates.</p></abstract>

Comparative study on the blast load response of woven and lattice core metallic sandwich panels

Sandwich structures are potential alternatives to monolithic plates for the purpose of absorbing energy and managing the impulse associated with blast loading. The study of sandwich structures subjected to blast loading is a rapidly expanding area of activity. Sandwich structures are extensively used in blast dissipation applications on account of their excellent physical and mechanical properties. These sacrificial cladding structures absorb energy through progressive plastic deformation of the front-facing plate and the core layer; thus minimizing the transfer of the peak force to the non-sacrificial structure. The core absorbs most of the energy and hence has a significant influence on the blast behavior of sandwich structures. The core layer can have several topologies, which in turn have various configurations. The present study numerically evaluated and compared the effectiveness of using Triangular Woven and Pyramidal Lattice core configurations in sandwich panels for resisting blast loads. The parametric study consisted of the effect of change in outer layer thicknesses of sandwich panels and the application of successive blast loads in the performance of the sandwich panels. The study was conducted for seven outer layer thickness combinations modeled in ANSYS Workbench Explicit Dynamics. All the models were subjected to a blast load with the same scaled distance. The comparison of the simulated results was used to determine the more suitable core configuration for dissipating blast loads. Pyramidal lattice panels were found to be 5% and 48% more efficient than a triangular woven panel of comparable relative core density under normal blast load and successive blast load respectively.

Залежність структури ливарних сплавів системи Al-Ni-La від їх хімічного складу

The peculiarities of cast Al-Ni-La alloys structure formation depending on the content and ratio of the main components are analyzed in the work. It is shown, that so far the studied system has been considered mainly for the creation of amorphous materials. At the same time, Al-Ni and Al-La systems have phase diagrams that allow us to consider double and triple alloys of these systems to create promising creep-resistant alloys for casting. At the same time, the peculiarities of their structure formation in this context were not determined. Samples with different contents of nickel and lanthanum were prepared for research and analyzed how each of the elements, their number and ratio affect the formation of their structural-phase state. It is shown, that low nickel content of about 2 wt. % and lanthanum up to 5 wt. % eutectic is formed like thin almost monolithic intermetallic plates. As the number of components increases and, accordingly, the number of eutectics increases, the dispersion of its components increases. The analysis of the alloy structure dependence due to studied system on their chemical composition showed that, most likely, during the formation of the eutectic, Al11La3 particles, which may have the form of nanosized fibers, are formed first of all. It should be noted that at the eutectic content of lanthanum in the alloys no primary-formed Al11La3 particles were found. This may indicate that nickel shifts the eutectic concentration of lanthanum toward higher values. At the same time, at the hypoeutectic concentration of lanthanum and the hypereutectic concentration of nickel, some Al11La3 formations were outside the regions of the main eutectic with nickel aluminide. Such questions necessitate further studies of the aluminum angle of the triple state diagram of the Al-Ni-La system. Keywords: Al-Ni-La system, creep-resistant cast aluminum alloys, structure, eutectic.

Hypervelocity impact response of monolithic UHMWPE and HDPE plates

When developing layered or architected protective structures to mitigate hypervelocity impacts (HVIs), understanding and characterizing the ultra-high rate response and energy dissipation of each constituent is critical. Incorporation of lightweight polymeric materials as intermediate or inner-most structural layers could optimize HVI damage resistance and tolerance without compromising cost or weight. One key challenge is developing a fundamental understanding of the effects of molecular architecture on the macroscopic dynamic material response and damage formation. In this work, two common and affordable thermoplastics, namely ultra-high molecular weight polyethylene (UHMWPE) and high density polyethylene (HDPE), were assessed. Flat square targets of two distinct sizes were subjected to a series of normal HVIs with 10 mm diameter 1050 aluminum spheres at velocities in the range 2–6.5 km/s. The debris cloud velocity, mass loss, and perforation radius were found to be functions of impact velocity for both materials. High-speed images show HVIs to UHMWPE resulted in quasi-brittle responses while HVIs to HDPE resulted in apparent bulk-melting of the material and large-scale plastic deformation. When subjected to HVIs in the tested range, UHMWPE plates exhibited greater mass loss than similar HDPE plates despite the perforation radii being larger in HDPE. This suggests that the momentum and kinetic energy of the debris clouds for UHMWPE targets were greater than that for HDPE targets subjected to identical impacts. These HVI experimental results combined with polymer material characterization data indicate that differences in the polymeric molecular structure and chemistry of the polyethylenes affect their macroscopic HVI performance.

Effect of incorporating Lode angle parameter into a fracture criterion in predicting ballistic impact behavior of double-layered 2024-T351 aluminum alloy plates against blunt projectiles

Recent studies showed that the ductility of some metals was affected by not only stress triaxiality but also Lode angle parameter. However, the majority of impact-related simulations used Lode independent fracture criteria. The necessity of incorporating Lode angle parameter into a fracture criterion in predicting ballistic impact behavior of monolithic 2024-T351 aluminum alloy (AA2024-T351) plates has been previously addressed in the work of Xiao et al. [1]. This paper serves as an extension by considering plates with double-layered configuration and the same total thickness. Ballistic impact tests were performed on 4.82 + 4.82 mm thick double-layered plates. Blunt projectiles with dimensions of Φ 12.66×50.56 mm3 and a nominal mass of 50 g were used, and the impact velocities ranged from 133.4 to 363.8 m/s. According to the experimentally obtained data, ballistic limit velocities (BLVs) were calculated and fracture patterns of post-test plates were analyzed. It was found that for double-layered configurations, the first plate failed by shear plugging and the second plate failed by tensile stretching and global deformation. By replacing monolithic plates with double-layered ones, the BLV increased from 138.4 to 180.1 m/s, a 30% improvement in ballistic resistance. Subsequently, numerical simulations of ballistic impact tests were performed by software ABAQUS/Explicit. Mechanical property of AA2024-T351 was described by Johnson-Cook (JC) plasticity model accompanied with either the Lode independent JC fracture criterion or the Lode dependent modified Mohr-Coulomb (MMC) fracture criterion. The numerical results were compared with those obtained from experiments. It was found that MMC criterion predicted BLVs more accurately than JC criterion. The prediction errors for MMC and JC criteria were respectively 3.3% and 11.4%, with the former being merely one-third of the latter. The overall failure modes of double-layered plates were correctly predicted by both JC and MMC fracture criteria. However, details of the fracture patterns, such as the formation of fragments, the shape and number of ejected plugs, and the initiation and propagation of cracks, were better captured by MMC criterion than by JC criterion. Detailed analysis shows that the stress state governing ballistic impact tests locates in the range where Lode angle parameter is strong enough to induce a significant difference between JC and MMC criteria. Under such stress state, the ductility of AA2024-T351 is correctly predicted by the Lode dependent MMC criterion but is overestimated by the Lode independent JC criterion.

Fabrication of Catalytic Converter with Different Materials and Comparison with Existing Materials in Addition to Analysis of Turbine Installed at the Exhaust of 4 Stroke SI Engine

Harmful pollutants (CO, NO, and unburnt hydrocarbons) coming out from the exhaust manifold of an engine must be converted into harmless gases by using catalytic converter. This field has seen vast research for increasing the conversion efficiency of pollutants by using different cheap metals. Nowadays, catalysts used in catalytic converter are noble metals, and they are also critical in the sense that they are not abundant on Earth. Platinum, palladium and rhodium are very expensive; hence, low-cost cars are not installed with catalytic converter, especially in third world countries. This research has been carried out to assess the catalytic activity of catalysts made from the salt/metal precursors, cerium sulphate tetra hydrate, manganese sulphate mono hydrate and copper sulphate penta hydrate that are not expensive and also less affected by the poison. Test sample catalysts were prepared through a coprecipitation method having different molar concentrations, and then tested for the conversion efficiency by applying the catalysts on ceramic plates by using flue gas analyzer. On the basis of the results, final catalysts were prepared and applied on a monolithic ceramic plate and then tested with regard to the resulting conversion rate of pollutants as compared to already installed catalytic converter. Moreover, turbine was installed in the exhaust passage to generate the power that would be utilized to run the electrical accessories of the engine. SOLIDWORKS were used for 3D CAD modeling and the flow analysis of turbine with radial inlet-axial outlet. In addition, ANSYS was used for stress-strain analysis.

In silico analysis of modular bone plates

BackgroundInventory management or immediate availability of fracture plates can be problematic since for each surgical intervention a specific plate of varying size and functionality must be ordered. Modularization of the standard monolithic plate is proposed to address this issue. MethodsThe effects of four different unit module design parameters (type, degree of modularization, connector screw diameter, sandwich ratio) on the plate bending stiffness and failure are investigated in a finite element four-point-bending analysis. A chosen, best-performing modular plate is then tested in silico for a simple diaphyseal tibial fracture scenario under anatomical compressional, torsional, and bending loads. ResultsA modularization strategy is proposed to match the monolithic plate bending properties as closely as possible. With the best combination of design parameters, a fully modularized equivalent length plate with a 42.3% decrease in stiffness and 46.2% decrease in strength could be assembled. The chosen modular plate also displayed sufficient mechanical performance under the fracture fixation scenarios for a potentially successful osteosynthesis. ConclusionsVia computational methods, the viability of the modularization strategy as an alternate to the traditional monolithic plate is demonstrated. As a further realized advantage, the modular plates can alleviate stress shielding thanks to the reduced stiffness.

Simulation study of potential time-of-flight capabilities for a multilayer DOI-PET detector with an independent readout structure

A multilayer depth-of-interaction positron emission tomography (DOI-PET) detector with an independent readout structure has a potential advantage as a time-of-flight (TOF)-PET detector. The thin scintillator block of each detector layer can afford an improved coincidence time resolution (CTR) of ∼100 ps because the photon transfer time spread within the scintillator inherently decreases. To evaluate the potential TOF capabilities of a multilayer DOI-PET detector, which consists of thin layers of a cerium-doped lutetium–yttrium oxyorthosilicate (LYSO:Ce) scintillator coupled to a multi-pixel photon counter (MPPC) array, we examined the detector’s CTR performance via Monte Carlo simulations. We used several types of scintillator structures: a monolithic plate, laser-processing array with 3.2 mm pitch, fine laser-processing array with 1.6 mm pitch, and pixelated array with 3.2 mm pitch, with 2, 4, 6, and 8 mm thickness values of a 25.6 mm × 25.6 mm scintillator cross-section. The MPPC array was composed of 3.0 mm × 3.0 mm photosensitive segments arranged in an 8 × 8 array. Here, we note that the CTR performance also significantly depends on the timing detection method, which generates a timing trigger signal for coincidence detection. Thus, we evaluated the CTRs for each scintillator structure by adopting four timing detection methods: using the total sum signal of 64 MPPC chips (T_sum), the maximum signal in the 64 MPPC chips (Max), the sum signal of a partial number of MPPC chips located at and in the vicinity of the γ-ray interaction position (P_sum), and the average of the timestamps generated at several MPPC chips (Ave). When using the T_sum for timing detection, the CTR full width at half-maximum values were ∼100 ps regardless of the scintillator structure. However, when using the Max signal approach, the CTRs of the monolithic plates, laser-processing arrays, and fine-pitch laser-processing arrays were drastically degraded with increasing thickness. On the other hand, the CTRs of the pixelated arrays exhibited almost no degradation. To improve the CTRs of the monolithic plate and the (fine-pitch) laser-processing array that exhibit a large light spread in the scintillator block, we applied the P_sum and Ave methods. The resulting CTRs significantly improved upon using P_sum; however, in the Ave approach the improvement effect disappeared when the thickness was <6 mm in case of our simulation.

Experimental study of the strength characteristics of fixation of the symphysis pubis with an original plate for the reconstruction of the anterior pelvic semi-ring

The destabilization of bone fixators has led to repeated surgical interventions that increased the risk of migrations of metal fixators, infectious and inflammatory complications as well. The modern trends in hip bone injury surgery are related to developing and using of metal fixators, which are effective in acute injury; however, sometimes the condition of the patient and the technical support of hospitals don’t allow performing surgery in the acute period, and these metal fixators are ineffective for chronic damage. Consequently, until now, the problem of finding the optimal design of structures for fixing chronic damage of anterior pelvic semi-ring which will be able to exclude its destabilization, is still of current interest.The purpose of the study: developing and experimental researching of durable features of original plate for reconstruction of the anterior pelvic semi-ring.Materials and methods: In order to ensure stable fixation of chronic pelvic injuries, the original metal plates have been worked out. They are made individually in accordance with the anatomical and functional structures of the anterior pelvic semi-ring of the patient with using additive technologies. The study of the reliability of the different variants of ostiosynthesis of the anterior pelvic semi-ring with using well-known pelvic plates and a new original design was carried out. Stability tests for different plate fixing methods and mechanical strength of metallophyxators were carried out on a universal test machine of LFM-50kN series.Results: one plate fixation in tensile test showed the lowest result – 0.341 kN, a low result of shear loads was received with the same object. The best result was shown by the polyaxial monolithic plate fixation in case of stretching – 0.51 kN at the shear loads – 0.591 kN. Necessary force applied to destabilizing of the metal structure while using a polyaxial monolithic plate was a half-higher than stretched, and a third higher than at shear loads, it demonstrates the benefits of using these metal fixators.Conclusion: It is experimentally confirmed that the polyaxial monolithic plate provides the highest stability of fixing anterior pelvic semi-ring indicator in contrast with fixing of one or two plates.

Ballistic impact resistance of additive manufactured high-strength maraging steel: An experimental study

Maraging steel is a low carbon steel known for its ultra high-strength after heat treatment. In combination with Additive Manufacturing (AM), the properties of maraging steel indicate potential to enable complex geometries and improved performance-to-weight ratios for ballistic protection. This study investigates the ballistic performance of AM maraging steel monolithic plates and profile panels fabricated by powder bed fusion. The mechanical properties of the maraging steel, both in the as-built state and after heat treatment, were revealed through quasi-static and dynamic tests in three different directions with respect to the build direction. Metallurgical studies were also conducted to investigate the microstructure of the material both before and after testing. The ballistic perforation resistance of the maraging steel samples was disclosed in a ballistic range by firing 7.62 mm APM2 bullets towards the different target configurations. Ballistic limit curves and velocities were obtained, demonstrating that the thickest heat-treated AM maraging steel plate has a particularly good potential for ballistic protection. The hard core of the armour piercing bullet broke in all tests and occasionally shattered during tests with heat-treated targets. However, due to the severe brittleness of the material, the targets showed significant fragmentation in some cases and most significantly for the profile panels.

High-throughput rat immunoglobulin G N-glycosylation profiling revealed subclass-specific changes associated with chronic stress

Immunoglobulin G (IgG) glycosylation corresponds well with immune system changes, so it can potentially be used as a biomarker for the consequences of chronic stress such as low-grade inflammation and enhanced immunosenescence in older animals. Here we present a high-throughput glycoproteomic workflow, including IgG enrichment, HILIC glycopeptide purification, and nano-LC-MS analysis of tryptic glycopeptides applied for the analysis of rat IgG. A cohort of 80 animals was exposed to seven stressors in a customized chronic stress protocol with blood and tissue sampling in three timepoints. Young female rats experienced an increase in agalactosylated glycoforms on IgG2a and IgG2c accompanied by a decrease in monogalactosylation. Among old females, increased galactosylation was observed in the IgG2b subclass, pointing to an anti-inflammatory activity of IgG. Additionally, IgG Fc N-glycosylation patterns in Sprague Dawley rats were analyzed, quantified, and reported for the first time. Our findings emphasize age-, sex- and subclass-dependent differences in IgG glycosylation related to chronic stress exposure, confirming the relevance of newly developed methods for further research in glycobiology of rodent immune response. SignificanceIn this study, we showed that a high-throughput streamlined methodology based on protein L 96-well monolithic plates for efficient rat IgG immunoaffinity enrichment from blood plasma, paired with appropriate tryptic glycopeptide preparation, HILIC-SPE enrichment, and nano-LC-MS methods was suitable for quick processing of large sample sets. We report a subclass-specific profiling and changes in rat IgG Fc galactosylation and adrenal gland immunohistochemistry of male and female animals exposed to a customized chronic stress protocol.

Influence of monolithic plate manufacturing technology on physical and mechanical characteristics of the coating

During operation in an open atmosphere, bridge structures are exposed to extreme natural and climatic conditions, chemicals and constantly changing temporary and dynamic loads. Bridge structures built in the 60s and 80s of the last century have approached a critical situation and require major repairs. Goal. The most vulnerable elements of the bridge structure are the upper part of the concrete span structures (slab) and waterproofing, so there was a question of strengthening the slabs and replacing the waterproofing layer. Metodology. When forecasting the durability of bridge structures, it is necessary to take into account the influence of temperature and humidity and climatic factors together with force factors. Result. The real necessity of mounting a monolithic reinforced concrete slab for strengthening a top slab of girder structures and putting a new waterproofing layer on it is shown. Originality. The technology of spraying a waterproofing layer that allows to waterproof a surface of any complexity evenly and reliably is offered. Practical value. Overhead monolithic slab enhances the bearing capacity of the power elements of the bridges and can be increased by 1.5–2 times.

Preparation and Electron-Beam Surface Modification of Novel TiNi Material for Medical Applications

A new approach to fabricate TiNi surfaces combining the advantages of both monolithic and porous materials for implants is used in this work. New materials were obtained by depositing a porous TiNi powder onto monolithic TiNi plates followed by sintering at 1200 °C. Then, further modification of the material surface with a high-current-pulsed electron beam (HCPEB) was carried out. Three materials obtained (one after sintering and two after subsequent beam treatment by 30 pulses with different pulse energy) were studied by XRD, SEM, EDX, surface profilometry, and by means of electrochemical measurements, including OCP and EIS. Structural and compositional changes caused by HCPEB treatment were investigated. Surface properties of the samples during their storage in saline for 10 days were studied and a model experiment with cell growth (MCF-7) was carried out for the unmodified sample with an electron beam to detect cell appearance on different surface locations.

Analysis of Anomalous Dynamic Responses of Fiber Metal Laminates Under Pulse Loading

Composed of metallic layers and composite plies, fiber metal laminates (FMLs) combine inherent advantages of metals and composites. The phenomenon of anomalous response behavior, in which the permanent deformation is in the opposite direction to the incoming pressure wave, has been discovered in dynamic responses of monolithic plate subjected to impulsive loading. In this study, dynamic responses of FML plates of various configurations are examined and compared against the responses of a monolithic plate using finite element analysis. It is found that under the load condition in which an anomalous dynamic behavior of an aluminum plate is observed, FMLs oscillate a few cycles before resting on permanent deformation, and the laminate thickness strongly affects the final deflection, which could be in the counter-intuitive direction or near the initial position of zero deflection depending on configuration and specification of FMLs. In addition, interaction of damage accumulation with deflection responses is investigated. The findings of this study can be useful for optimal design of FMLs intended for usage under extreme loadings.

Numerical analysis of linear and nonlinear buckling instability of plates made of topologically interlocked materials

Topologically interlocked materials (TIMs) are an emerging class of architectured materials that each of block is supported by their neighboring blocks without any connector, which is inspired by microstructures observed in nature. Therefore, they showed alluring attributes such as resistance to impact, toughness, high flexibility even when using brittle materials, and high crack propagation resistance. In these structures, the presence of lateral compressive force, applied on peripheral blocks, ensures the integrity and identified properties. Lateral load, however, can adversely affect TIM plates and cause instability, and initiate buckling. In the present study, to focus on the buckling behavior of TIM plates due to the lateral force, a finite element model of TIM plates, made of tetrahedral blocks, was first validated using numerical results available in the literature and then analyzed. In this regard, an appropriate procedure has been presented to simulate the possible instability of these structures. Unlike monolithic plates, geometric parameters of TIM plates are dependent and this makes their parametric study more challenging. Therefore, some case studies have been accomplished to illustrate the effect of diverse parameters. The current study indicates that increasing the assembly plate length and decreasing its thickness causes a reduction of buckling load; nevertheless, it is necessary to mention that the thickness variation is a more impressive factor.

Effect of grinding adjustments on the color of monolithic zirconia

Statement of problemMonolithic zirconia restorations have become popular because of their excellent mechanical properties and acceptable esthetics. While the biomechanical properties of zirconia have been investigated, research into their esthetic properties is sparse. Zirconia can be colored by infiltration before sintering, although how occlusal adjustment can affect restoration color is unclear. PurposeThe purpose of this in vitro study was to analyze the color of differently characterized monolithic white and precolored zirconia specimens after standardized grinding. Material and methodsWhite and precolored monolithic zirconia plates (Cercon ht) (n=36) were stained by infiltration with target colors Vita A2, A3.5, and A4. In a standardized experimental arrangement, all plates were ground in 9 steps, and the color was measured with a spectroradiometer at each step. Color differences (ΔE00) were analyzed by using regression analysis, the Kruskal-Wallis test, and the inverse prediction with confidence intervals (α=.05). ResultsMechanical material removal had a significant effect on the color stability (P<.05) of both white and precolored monolithic zirconia. For each grinding step and each target color, the precolored groups had a significantly lower ΔE00 mean than the white groups (P<.05), except at the 20-μm step for groups W-A4 and P-A4 (P>.05). For target color A2, the difference was significant with P<.001 at all 9 grinding steps. For target color A3.5, the difference was significant with P=.003 at grinding level 20 μm, and P<.001 for all other grinding steps. For target color A4, the difference was not significant with P=.603 at grinding level 20 μm, whereas the difference was significant with P=.007 at grinding level 50 μm, and with P<.001 for all other grinding steps. ConclusionsPrecolored zirconia had less color change after grinding than white zirconia. This study established grinding depths for white and precolored zirconia corresponding to color perceptibility and acceptability thresholds.

Impact of polyurea-coated metallic targets: Computational framework

Polyurea elastomer is known to exhibit advantageous impact-mitigation characteristics and thus can improve the dynamic performance of various components and structures. This study identifies the mechanisms of dynamic response of thin metallic plates, covered by a frontal polyurea layer, using a physically verified, custom material model for two-part polyurea implemented within a finite-element-method framework. A linear increase in the ballistic performance of a target with polymer coating is consistent with experimental work captured for the first time in a numerical study. A reported ballistic-limit improvement of 7.4 m s−1 per millimetre increase of polyurea thickness for frontal-layer thicknesses higher than 4 mm on the thin monolithic plate was established. In contrast, the application of polyurea coating thinner than 4 mm resulted in a diminished ballistic performance of the target. These outcomes are attributed to significant alterations in the energy-absorbing capacity of thin plates with the introduction of the polyurea layer that strongly depend on the impact velocity, polymer thickness, and interfacial interactions.

Effect of bolt tightening on the fatigue behavior of GLARE double shear lap joints

In this paper, the effect of bolt torque tightening has been investigated on the fatigue behavior of GLARE in double shear lap configuration. To do so, experimental fatigue tests were conducted using GLARE3-5/4-0.4 specimens with applied torques of 0 (finger tightened), 2 and 4 Nm at different cyclic longitudinal load ranges to achieve the stress-life (S-N) curves. The results revealed that applying and increasing the clamping force enhances the fatigue life of the GLARE specimens. Furthermore, comparison of fatigue test results of GLARE and available monolithic aluminum alloy 2024-T3 plates indicated when the applied load range is low, the effect of clamping force is more noticeable in GLARE specimens due to longer fatigue crack growth life of GLARE. Also, the occurrence of fretting fatigue didn’t reduce the fatigue life of GLARE specimens considerably in contrary to aluminum sheets because of the laminated structure of GLARE. The obtained results can provide insights in designing bolted GLARE joints with superior fatigue in-service performance.

A Dimensionless Number for Response of Blast Loaded Steel Plates

The response of monolithic steel plates subjected to blast was extensively studied, and dozens of dimensionless numbers were proposed to predict the response. While the existing dimensionless numbers are not convenient to use in some scenarios with relatively complicated conditions, the dimensionless number proposed for blast loaded steel plates based on dimensional analysis extends the range of application. Different from other dimensionless numbers, the properties of medium with which the blast load transmits are incorporated to extend the application range to more general scenarios. The responses of the plate subjected to both near-field blast with non-uniform load and far-field blast with uniform load, i.e. both the external and internal blasts (for steel boxes), are reasonably predicted. The physical implication of the proposed dimensionless number is clear in that the media properties, geometrical features, characteristics of material, and loading are incorporated, which are readily available in test. A variety of test data are used to validate the applicability and versatility of the proposed dimensionless number.